This invention relates generally to display systems for helmets and in particular for display systems for motorcycle helmets.
Heads-up displays have been suggested for implementation in a multitude of transportation applications including automobiles, aircraft and motorcycles. Heads-up displays typically comprise an image projector, an optical collimator; and a beam splitter (combiner). The beam splitter is typically an angled flat piece of transparent or partially reflective material located directly in front of the viewer. The beam splitter reflects the image from the image projector in such a way that the user is able to see the field of view and the projected image at the same time. The optical collimator focuses the image from the image projector into parallel rays of light so that the user sees a virtual image that appears to be at an infinite distance.
The necessity of having a beam splitter as part of a heads-up display causes little inconvenience in automobiles and aircraft where there is a significant amount of space between the user and the front windscreen of the vehicle within which to mount the beam splitter. For motorcycles, however, installing a beam splitter in the limited space between the rider's face and the helmet windscreen presents significant design obstacles. U.S. Pat. No. 5,537,092 issued to Suzuki et al. suggests simplifying the information displayed to a motorcycle rider (e.g. by using a linear array of LEDs) and projecting it as a virtual image along the base of the visor (partially obstructing the field of view) as a means of overcoming the space limitations inherent in helmet information displays. This approach, however, severely limits the amount of information that can be communicated to the motorcycle rider and results in a reduction of the rider's field of view.
Additionally, as the demand for more and more real-time display of information increases, the processor speed and power consumption necessary to accommodate the demands also increases. In a wireless environment, this dictates the need for larger and heavier batteries in the helmet battery pack, use of tethered batteries and/or powering the helmet with a cable from the vehicle power system. US patent application 2009/0109292 to Ennis for example discloses a video camera system including a heads-up display that is operated from a battery belt pack connected to the camera by a cable. This is not an ideal implementation for a motorcycle helmet since a cable connected between the motorcyclist's helmet and a belt-mounted battery would be cumbersome especially with the exposed cable subjected to windblast at high speeds.